Contribution of labeled carbon dioxide to PET imaging of carbon-11-labeled compounds.

摘要: 11CO2 is one of the major metabolites many [11C]-labeled radiopharmaceuticals, including glucose, thymidine, acetate, amino acids, and fatty acids. Our data contradict notion that contribution labeled CO2 to PET images can be disregarded because its rapid elimination through lungs. We have measured retention excretion in dogs after intravenous injection CO2/HCO3-, which had been equilibrated ex vivo with blood. Only 58% label was exhaled as over first 60 min injection, rest retained body. The [11C]thymidine ring-2 position or [11C]acetate carboxylate resulted production large amounts exhalation about 47% 23%, respectively, injected min. At 10 either [11C] approximately 60% 70% total blood activity bicarbonate. On other hand, use [1-11C]glucose only 5% dose CO2/HCO3- made up less than 10% at results indicate distribution needs considered when interpreting obtained from 11C-labeled compounds.